ggx145 wrote:
Does it take filters? I have the sigma, minor problem that it does not take polarizers but has a mount for ND in the back.
It’s like the other superwide zooms with a filter slot on the rear. Hopefully Kass will make an adapter like they did for the Sony version. I suspect they will if this lens becomes as popular as I assume it will.
For thread posterity. I got my A7R6 a few hours ago, so keep in mind that I'm not at all facile with the camera yet. That disclaimer, I decided to try the lens out on stars. But these are from my Silicon Valley backyard with tons of light pollution, so keep that in mind too please!
Basically, as full images they look pretty decent, but zooming into 100% you definitely see the optical warts. I doubt diehard astro enthusiasts will fawn much over this lens. However, I think it's definitely useable for the occasional landscape shooter who happens to already own it and wants to grab the occasional general astro landscape. Basically that was my interest in this test and my takeaway is this lens will serve that purpose just fine for me. There also may be lens copy variation and this may be a bad copy, IDK... The reality is 12 through 16 all pretty much looked like what I'm posting below. In fact I had to look at exif to know which focal I was at when viewing at 100%. The 18 to 20 range shows a little bit more coma at the corners. This could be due to the added focal magnification or simply worse coma or both. Again, this is not visible in the full image at normal viewing distances. Below is a full-frame image and 3 100% crops as labeled. Also these are all 2048px crops so make sure to view them at that size as browsers will enlarge images in this forum.
PS Edit: For whatever reason there appears to be some color artifacting/banding in the full jpeg as posted here that isn't in my original, I've triple checked it and even re-posted, so can't explain that.
Full image
ILCE-7RM6TAMRON 12-20mm F2.8 A084 E lens16mmf/2.84s3200 ISO0.0 EV
Okay, one more I had to share just for giggles. I was out testing all my lenses on the A7R6 body this morning, and this was the very first capture using the Tamron 12-20 at 12mm wide open. Upon reviewing it, I saw this FYI, full is sized to 2048 wide while crop is sized to 4056 to better see it. (Yes, that's a dragonfly )
full image at 2048 wide
ILCE-7RM6TAMRON 12-20mm F2.8 A084 E lens12mmf/2.81/3200s100 ISO0.0 EV
FYI, full is sized to 2048 wide while crop is sized to 4056 to better see it. (Yes, that's a dragonfly 
) 
